Integrated circuits in a computing system typically communicate using electrical signals that pass through small wires embedded within a printed circuit board. Integrated circuits are also known that communicate with optical signals. Such optical signals have advantages in bandwidth and reduced electromagnetic interference. Some optical communication systems are proposed to use free-space, line-of-sight light propagation; others rely on integrated assemblies of light controlling elements.
Prior-art optical interconnection systems are often expensive, for example including elements such as embedded fiber optic cables, connectors, mirrors, holographic elements, and graded index materials or lenses. Such structures are difficult to make and assemble. U.S. Pat. No. 6,755,573 describes a full-mesh optical interconnect used in backplanes that includes power distribution. U.S. Pat. No. 6,320,863 illustrates another backplane structure with optical fiber communication. Micro-lenses associated with a corresponding optical transmission port are also known as disclosed in U.S. Pat. No. 8,437,085.
It is also known to make optical elements using imprinting methods for embossing a resin layer to form a plurality of micro-protrusions for an optical element, for example a brightness-enhancing sheet for a liquid-crystal display backlight module as describe in U.S. Patent Application Publication No. 2008/0079183.